package com.bangcommunity.bbframe.common.utils.crypt;

import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.spec.SecretKeySpec;
import java.math.BigInteger;
import java.security.MessageDigest;
import java.security.SecureRandom;

/**
 * TODO 一句话描述该类用途
 * <p/>
 * 创建时间: 15/10/21 下午4:38<br/>
 *
 * @author tanghc
 * @since v0.0.1
 */
public class AESUtil {

    /**
     * 编码工具类 1.将byte[]转为各种进制的字符串 2.base 64 encode 3.base 64 decode 4.获取byte[]的md5值 5.获取字符串md5值
     * 6.结合base64实现md5加密 7.AES加密 8.AES加密为base 64 code 9.AES解密 10.将base 64 code AES解密
     * 
     * @author uikoo9
     * @version 0.0.7.20140601
     */

    public static void main(String[] args) throws Exception {

        String content = "我爱你";
        System.out.println("加密前：" + content);

        String key = "123456";
        System.out.println("加密密钥和解密密钥：" + key);

        String encrypt = aesEncrypt(content, key);
        System.out.println("加密后：" + encrypt);

        String decrypt = aesDecrypt(encrypt, key);
        System.out.println("解密后：" + decrypt);
    }

    /**
     * 将byte[]转为各种进制的字符串
     * 
     * @param bytes
     *            byte[]
     * @param radix
     *            可以转换进制的范围，从Character.MIN_RADIX到Character.MAX_RADIX，超出范围后变为10进制
     * @return 转换后的字符串
     */
    public static String binary(byte[] bytes, int radix) {
        return new BigInteger(1, bytes).toString(radix);// 这里的1代表正数
    }

    /**
     * base 64 encode
     * 
     * @param bytes
     *            待编码的byte[]
     * @return 编码后的base 64 code
     */
    public static String base64Encode(byte[] bytes) {
        return new BASE64Encoder().encode(bytes);
    }

    /**
     * base 64 decode
     * 
     * @param base64Code
     *            待解码的base 64 code
     * @return 解码后的byte[]
     * @throws Exception
     */
    public static byte[] base64Decode(String base64Code) throws Exception {
        return new BASE64Decoder().decodeBuffer(base64Code);
    }

    /**
     * 获取byte[]的md5值
     * 
     * @param bytes
     *            byte[]
     * @return md5
     * @throws Exception
     */
    public static byte[] md5(byte[] bytes) throws Exception {
        MessageDigest md = MessageDigest.getInstance("MD5");
        md.update(bytes);

        return md.digest();
    }

    /**
     * 获取字符串md5值
     * 
     * @param msg
     * @return md5
     * @throws Exception
     */
    public static byte[] md5(String msg) throws Exception {
        return md5(msg.getBytes());
    }

    /**
     * 结合base64实现md5加密
     * 
     * @param msg
     *            待加密字符串
     * @return 获取md5后转为base64
     * @throws Exception
     */
    public static String md5Encrypt(String msg) throws Exception {
        return base64Encode(md5(msg));
    }

    /**
     * AES加密
     * 
     * @param content
     *            待加密的内容
     * @param encryptKey
     *            加密密钥
     * @return 加密后的byte[]
     * @throws Exception
     */
    public static byte[] aesEncryptToBytes(String content, String encryptKey) throws Exception {
        KeyGenerator kgen = KeyGenerator.getInstance("AES");
        SecureRandom secureRandom = SecureRandom.getInstance("SHA1PRNG");
        secureRandom.setSeed(encryptKey.getBytes());
        kgen.init(128, secureRandom);

        Cipher cipher = Cipher.getInstance("AES");
        cipher.init(Cipher.ENCRYPT_MODE, new SecretKeySpec(kgen.generateKey().getEncoded(), "AES"));

        return cipher.doFinal(content.getBytes("utf-8"));
    }

    /**
     * AES加密为base 64 code
     * 
     * @param content
     *            待加密的内容
     * @param encryptKey
     *            加密密钥
     * @return 加密后的base 64 code
     * @throws Exception
     */
    public static String aesEncrypt(String content, String encryptKey) throws Exception {
        return base64Encode(aesEncryptToBytes(content, encryptKey));
    }

    /**
     * AES解密
     * 
     * @param encryptBytes
     *            待解密的byte[]
     * @param decryptKey
     *            解密密钥
     * @return 解密后的String
     * @throws Exception
     */
    public static String aesDecryptByBytes(byte[] encryptBytes, String decryptKey) throws Exception {
        KeyGenerator kgen = KeyGenerator.getInstance("AES");
        SecureRandom secureRandom = SecureRandom.getInstance("SHA1PRNG");
        secureRandom.setSeed(decryptKey.getBytes());
        kgen.init(128, secureRandom);

        Cipher cipher = Cipher.getInstance("AES");
        cipher.init(Cipher.DECRYPT_MODE, new SecretKeySpec(kgen.generateKey().getEncoded(), "AES"));
        byte[] decryptBytes = cipher.doFinal(encryptBytes);

        return new String(decryptBytes);
    }

    /**
     * 将base 64 code AES解密
     * 
     * @param encryptStr
     *            待解密的base 64 code
     * @param decryptKey
     *            解密密钥
     * @return 解密后的string
     * @throws Exception
     */
    public static String aesDecrypt(String encryptStr, String decryptKey) throws Exception {
        return aesDecryptByBytes(base64Decode(encryptStr), decryptKey);
    }

}
